The projects fall into the two major categories of neuroendocrinology and renal physiology, and more specifically, into the areas of hormone production and the effects of hormones on the renal countercurrent system. By and large, the projects will utilize inherited disorders in animals, both as analogue model of human disease and, through the use of genetically segregating generations, as tools in biomedical research. In the area of hormone production, the following problems will be investigated: 1) qualitative and quantitative aspects of neurophysin biosynthesis; 2) an attempt to develop a radioligand assay for vasopressin and oxytocin; and 3) growth hormone deficiency as a cause of stunted growth in hypothalamic diabetes insipidus. The following problems will deal with the effect of hormones on the renal countercurrent system: 4) further identification of the cause of vasopressin (ADH)-resiitant diabetes insipidus in the so-called "DI plus/plus Severe" genotype of mice; 5) the role of female sex hormones (mainly estrogen) in the renal concentrating mechanism; and 6) an attempt to further characterize the cause of the slow correction of urinary concentration during the treatment of hypothalamic diabetes insipidus. The following techniques will be employed: thin layer chromatography; polyacrilamide gel electrophoresis; radioligand assays; renal micropuncture; tracer microinjection; chemical analysis of renal tissues; a genetic approach utilizing the independent segregation of genes in second generation hybrids; measurement of single nephron glomerular filtration rates.